G
goodboy_1507


Giải phương trình
[TEX] ( sin^3 \frac{x}{2} +\frac{1}{sin^3 \frac{x}{2}}) ^2 + ( cos^3 \frac{x}{2} + \frac{1}{cos^3 \frac{x}{2}} )^2 = \frac{81.Cos^2 4x}{4} [/TEX]
[TEX] ( sin^3 \frac{x}{2} +\frac{1}{sin^3 \frac{x}{2}}) ^2 + ( cos^3 \frac{x}{2} + \frac{1}{cos^3 \frac{x}{2}} )^2 = \frac{81.Cos^2 4x}{4} [/TEX]